Highly mixed impacts of near-future climate change on stock productivity proxies in the North East Atlantic

Impacts of climate change on ocean productivity sustaining world fisheries are predominantly negative but vary greatly among regions. We assessed how 39 fisheries resources—ranging from data-poor to data-rich stocks—in the North East Atlantic are most likely affected under the intermediate climate emission scenario RCP4.5 towards 2050. This region is one of the most productive waters in the world but subjected to pronounced climate change, especially in the northernmost part. In this climate impact assessment, we applied a hybrid solution combining expert opinions (scorings)—supported by an extensive literature review—with mechanistic approaches, considering stocks in three different large marine ecosystems, the North, Norwegian and Barents Seas. This approach enabled calculation of the directional effect as a function of climate exposure and sensitivity attributes (life-history schedules), focusing on local stocks (conspecifics) across latitudes rather than the species in general. The resulting synopsis (50–82°N) contributes substantially to global assessments of major fisheries (FAO, The State of World Fisheries and Aquaculture, 2020), complementing related studies off northeast United States (35–45°N) (Hare et al., PLoS One, 2016, 11, e0146756) and Portugal (37–42°N) (Bueno-Pardo et al., Scientific Reports, 2021, 11, 2958). Contrary to prevailing fisheries forecasts elsewhere, we found that most assessed stocks respond positively. However, the underlying, extensive environmental clines implied that North East Atlantic stocks will develop entirely different depending upon the encountered stressors: cold-temperate stocks at the southern and Arctic stocks at the northern fringes appeared severely negatively impacted, whereas warm-temperate stocks expanding from south were found to do well along with cold-temperate stocks currently inhabiting below-optimal temperatures in the northern subregion.publishedVersio

Report of the Working Group on Commercial Catches (WGCATCH)

The Working Group on Commercial Catches (WGCATCH), chaired by Mike Arm- strong (UK) and Hans Gerritsen (Ireland), met in ICES HQ, Copenhagen, Denmark, 10–14 November 2014. The meeting was attended by 34 experts from 21 laboratories or organizations, covering 16 countries. Currently, an important task for WGCATCH is to improve and review sampling sur- vey designs for commercial fisheries, particularly those for estimating quantities and size or age compositions of landings and discards and providing data quality indica- tors. However, the scope of WGCATCH is broader than this, covering many other aspects of collection and analysis of data on fishing activities and catches. This will be end-user driven, and coordinated with the work of other ICES data EGs such as the Working Group on Biological Parameters (WGBIOP), the Planning Group on Data Needs for Assessments and Advice (PGDATA) and the Working Group on Recrea- tional Fisheries Surveys (WGRFS) to ensure synergy and efficiency. The report of the meeting commences with background information on the formation of WGCATCH and its overall role. The remainder of the report provides the out- comes for each of the Terms of Reference (ToRs) and responses to external requests, the proposed future work plan and the ToRs for the 2015 meeting. The group formed two large subgroups to deal with the two major terms of reference which are the development of guidelines for carrying out sampling of catches on shore and the provision of advice on adapting sampling programmes to deal with the landing obligation. In order to evaluate methods and develop guidelines for best practice in carrying out sampling of commercial sampling of commercial fish catches onshore, a question- naire was circulated before the meeting. This questionnaire was structured around guidelines developed by the ICES Workshop on Practical Implementation of Statisti- cally Sound Catch Sampling Programmes (WKPICS) for best practice at each stage of the sampling process, and asked for a description of current practices at each of these stages. Based on these questionnaires, common and specific problems were cata- logued and potential solutions were identified. At the same time, the discussion of the questionnaires provided a form of peer-review of the sampling designs and iden- tified where improvements could be made. WGCATCH provided guidelines for de- signing a sampling survey and summarized earlier guidelines provided by the 2010 Workshop on methods for merging métiers for fishery based sampling (WKMERGE) The other main subject addressed by WGCATCH concerns the provision of advice on adapting sampling protocols to deal with the impact of the introduction of the land- ing obligation, which will alter discarding practices and result in additional catego- ries of catch being landed. A second questionnaire was circulated before the meeting to allow the group to identify the fleets that will be affected and possible issues that are anticipated, as well as to propose solutions to adapt existing monitoring and sampling schemes and to quantify bias resulting from the introduction of this regula- tion. WGCATCH outlined a range of likely scenarios and the expected effects of these on fishery sampling programmes, and developed guidelines for adapting sam- pling schemes. The group also explored a range of analyses that could be conducted in order to quantify bias resulting from the introduction of the landing obligation. Finally a number of pilot studies/case studies were summarized, highlighting the practical issues involve

Separation of Norwegian coastal cod and Northeast Arctic cod by otolith morphometry

For stock assessment purposes, Atlantic cod (Gadus morhua) from the coastal and offshore regions off northern Norway is usually allocated to Norwegian coastal cod (NCC) and Northeast Arctic cod (NEAC) by internal morphological features of their otoliths. As this classification is subject to individual interpretation, this study investigated an alternative objective approach for the separation of the two cod groups, using otolith shape analysis. Otolith samples from coastal areas along northern Norway and from the Barents Sea were analysed by univariate shape descriptors and Elliptical Fourier Analysis (EFA). When combining those methods, the classification score was 89% for NCC and 90% for NEAC. When genetic typing data (Pan I marker) were used as reference, the classification scores were reduced to 83% for NCC and 76% for NEAC. These results imply that differences in internal otolith morphology are translated to a large extent into the outer shape, but that those cannot directly be linked to genetic structure. Environmental conditions, however, seem to have a considerable influence on how otolith growth increments and consequently otolith shapes are formed. As the various fjord systems in Norway provide local habitats and as differences within the NCC with regard to genetic structure and life-history parameters had been found in earlier studies, variation of NCC otolith shapes between three coastal regions was also examined. The region classification scores for reader-typed NCC varied between 60% and 81%. Apart from the outer shape analyses, experimental work on the detection of internal (annuli) shapes was carried out and will be presented as work in progress. Keywords: Stock identification; Otolith shape analysis; Northeast Atlantic; Norway; Atlantic cod; Gadus morhu

Anglerfish (Lophius spp) in Nordic waters

The demand for anglerfish for human consumption has increased in the last couple of decades because of the delicate consistency of its meat. Accordingly, the fishing pressure has increased considerably in all Nordic fishing regions. Relatively little has, however, hitherto been known about anglerfish biology and ecology. Assessment and management of Nordic anglerfish stocks is difficult to conduct due to the paucity of fisheries and biological data. Answers to questions regarding the spawning behaviour, migratory behaviour and juvenile drift, as well as more knowledge about growth, sexual maturation, diet and natural mortality, would thus form crucial contributions to present and future management of Nordic anglerfish stocks. This report presents a review of the status of current knowledge and research on the biology, ecology, fisheries and stock management of anglerfish in Nordic and European countries, including results and publications from a three-year Nordic cooperative anglerfish research project (2002-2004). Preliminary attempts were made at estimating current levels of fishing mortality in the Nordic regions, and the yield and spawning stock per anglerfish recruit. Recommendations on future research are also given

A Time History of Pre- and Post-Bomb Radiocarbon in the Barents Sea Derived from Arcto-Norwegian Cod Otoliths

From the 17th International Radiocarbon Conference held in Jerusalem, Israel, June 18-23, 2000.Radiocarbon measured in seawater dissolved inorganic carbon (DIC) can be used to investigate ocean circulation, atmosphere/ocean carbon flux, and provide powerful constraints for the fine-tuning of general circulation models (GCMs). Time series of 14C in seawater are derived most frequently from annual bands of hermatypic corals. However, this proxy is unavailable in temperate and polar oceans. Fish otoliths, calcium carbonate auditory, and gravity receptors in the membranous labyrinths of teleost fishes, can act as proxies for 14C in most oceans and at most depths. Arcto-Norwegian cod otoliths are suited to this application due to the well-defined distribution of this species in the Barents Sea, the ability to determine ages of individual Arcto-Norwegian cod with a high level of accuracy, and the availability of archived otoliths collectedfor fisheries research over the past 60 years. Using measurements of 14C derived from Arcto-Norwegian cod otoliths, wepresent the first preand post-bomb time series (1919-1992) of 14C from polar seas and consider the significance of these data in relation to ocean circulation and atmosphere/ocean flux of 14C. The data provide evidence for a minor Suess effect of only 0.2‰ per year between 1919 and 1950. Bomb 14C was evident in the Barents Sea as early as 1957 and the highest 14C value was measured in an otolith core from a cod with a birth date of 1967. The otolith 14C data display key features common to records of 14C obtained from a Georges Bank mollusc and corals from the tropical and subtropical North Atlantic.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Kunnskapsstatus leppefisk : Utfordringer i et økende fiskeri

Over the past few years there has been a rapid increase in the use of wrasses as cleanerfish for sealice on salmon farms. During 2010, the landed catch of wrasse was 440 tons, more than twice the 2009 catch and nearly ten times the 2008 catch. This rapid and exrteme increase in the fishing pressure on these species has occurred despite very limited knowledge of their biology, ecology and population dynamics. This has led to justifiable concern about the sustainibility of this resource. Wrasse demonstrate specialized life history traits. Many species change sex during their lifetime and exhibit species-specific mating behaviour, including nest building and parental care of eggs. This mating strategy lends to limited dispersal of offspring, ond only goldsinny wrasse have pelagic eggs. Many adult individuals are stationary, thereby creating a population struction dominated by Iocal populations. This population structure is also documented through genetic sludies in corkwing and goldsinny wrasse. Small local populations are more vulnerable to overfishing and possible extinction of local genetic adaptations. Studies of growth of wild wrasse demonstrate that goldsinsy and rock cook grow slower than corkwing. This suggests that the first two will take longer to recover from heavy fishing pressure. Results presented here suggest that both the composition of species and the size distribution; vary between habitats, particularly between exposed and sheltered areas. More precise and complete information on population structure. growth and maturation of these species is required 10 provide the knowledge base for sustainable fishing. Better knowledge of the health and welfare of these species - in salmon co-culture scenarios - is also needed

Current knowledge on wrasse - challenges in an increasing fishery

Over the past few years there has been a rapid increase in the use of wrasses as cleanerfish for sealice on salmon farms. During 2010, the landed catch of wrasse was 440 tons, more than twice the 2009 catch and nearly ten times the 2008 catch. This rapid and exrteme increase in the fishing pressure on these species has occurred despite very limited knowledge of their biology, ecology and population dynamics. This has led to justifiable concern about the sustainibility of this resource. Wrasse demonstrate specialized life history traits. Many species change sex during their lifetime and exhibit species-specific mating behaviour, including nest building and parental care of eggs. This mating strategy lends to limited dispersal of offspring, ond only goldsinny wrasse have pelagic eggs. Many adult individuals are stationary, thereby creating a population struction dominated by Iocal populations. This population structure is also documented through genetic sludies in corkwing and goldsinny wrasse. Small local populations are more vulnerable to overfishing and possible extinction of local genetic adaptations. Studies of growth of wild wrasse demonstrate that goldsinsy and rock cook grow slower than corkwing. This suggests that the first two will take longer to recover from heavy fishing pressure. Results presented here suggest that both the composition of species and the size distribution; vary between habitats, particularly between exposed and sheltered areas. More precise and complete information on population structure. growth and maturation of these species is required 10 provide the knowledge base for sustainable fishing. Better knowledge of the health and welfare of these species - in salmon co-culture scenarios - is also needed